Objective

This study aims to incorporate 2:1 MgAl and 2:1 CaAl layered double hydroxides (LDHs) in experimental dental-composites to render them fluoride rechargeable. The effect of LDH on fluoride absorption and release, and their physico-mechanical properties are investigated.

Methods

2:1 CaAl and 2:1 MgAl LDH-composite discs prepared with 0, 10 and 30 wt% LDH were charged with fluoride (48 h) and transferred to deionized water (DW)/artificial saliva (AS). Fluoride release/re-release was measured every 24 h (ion-selective electrodes) with DW/AS replaced daily, and samples re-charged (5 min) with fluoride every 2 days. Five absorption-release cycles were conducted over 10 days. CaAl and MgAl LDH rod-shaped specimens (dry and hydrated; 0, 10 and 30 wt%) were studied for flexural strength and modulus. CaAl and MgAl LDH-composite discs (0, 10, 30 and 45 wt% LDH) were prepared to study water uptake (over 7 weeks), water desorption (3 weeks), diffusion coefficients, solubility and cation release (ICP-OES).

Results

CaAl LDH and MgAl LDH-composites significantly increased the amount of fluoride released in both media (P < 0.05). In AS, the mean release after every recharge was greater for MgAl LDH-composites compared to CaAl LDH-composites (P < 0.05). After every recharge, the fluoride release was greater than the previous release cycle (P < 0.05) for all LDH-composites. Physico-mechanical properties of the LDH-composites demonstrated similar values to those reported in literature. The solubility and cation release showed a linear increase with LDH loading.

Significance

LDH-composites repeatedly absorbed/released fluoride and maintained desired physico-mechanical properties. A sustained low-level fluoride release with LDH-composites could lead to a potential breakthrough in preventing early stage carious-lesions.

中文翻译：

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新型的含MgAl和CaAl层状双氢氧化物（LDH）的可充氟牙科复合材料。

目的

这项研究的目的是在实验性牙科复合物中掺入2：1 MgAl和2：1 CaAl层状双氢氧化物（LDHs），使它们具有可充氟的功能。研究了LDH对氟化物吸收和释放的影响及其物理机械性能。

方法

将由0、10和30 wt％LDH制备的2：1 CaAl和2：1 MgAl LDH复合材料圆片装入氟化物（48小时），然后转移到去离子水（DW）/人工唾液（AS）中。每天更换DW / AS，每24小时（离子选择电极）测量一次氟化物的释放/再释放，并且每2天用氟化物对样品重新充电（5分钟）。在10天内进行了五个吸收释放循环。研究了CaAl和MgAl LDH棒状样品（干燥和水合； 0、10和30 wt％）的弯曲强度和模量。制备了CaAl和MgAl LDH复合圆盘（LDH的重量百分比为0、10、30和45），以研究吸水量（超过7周），水脱附（3周），扩散系数，溶解度和阳离子释放量（ICP-OES） 。

结果

CaAl LDH和MgAl LDH复合物显着增加了两种介质中释放的氟化物量（P  <0.05）。在AS中，与CaAl LDH复合材料相比，MgAl LDH复合材料每次充电后的平均释放量更大（P  <0.05）。每次充电后， 所有LDH复合材料的氟化物释放量均大于先前的释放周期（P <0.05）。LDH复合材料的物理机械性能与文献报道的相似。溶解度和阳离子释放随LDH负载呈线性增加。

意义

LDH复合物会反复吸收/释放氟化物，并保持所需的物理机械性能。LDH复合物持续释放的低水平氟化物可能导致预防早期龋齿病变方面的潜在突破。